Balance Sheet Components - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Sep. 30, 2024
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 184,637	$ 178,163
Less: Accumulated depreciation and amortization	(87,494)	(75,643)
Property and equipment, net	97,143	102,520
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	101,067	99,528
Furniture, fixtures and other equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,941	2,944
Vehicles
Property, Plant and Equipment [Line Items]
Property and equipment, gross	211	211
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,392	3,249
Computer software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	10,270	10,095
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	57,457	57,448
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 9,299	$ 4,688